1. Field of the Invention
The present invention relates generally to circuit board electrical connectors and particularly to a circuit board electrical connector which makes a so-called "pitch conversion" to thereby connect a first external member to a second external member having a contact arranging pitch different from that of the first external member.
2. Description of the Related Art
In FIG. 1, a circuit board 51 has circuit conductors on the upper surface thereof for connection to the connection portions of contact elements. An electrical connector 52 is attached to the upper surface of the circuit board 51 for receiving two cards 53 or other external members. Contact elements are arranged within the connector 52 in upper and lower planes in the direction perpendicular to the paper sheet, The contact portions of the contact elements are arranged within a housing 52A for contact with the corresponding circuit conductors of the card 53. The connection portions 54 of the contact elements project from the housing 52A.
A conversion connector 56 has a lower connector 56B connected to the circuit board 51 and an upper connector 56A connected to a conversion board 55. The other end of the conversion board 55 is coupled to the housing 52A. The upper connector 56A is connected to the lower connector 56B. Circuit conductors are formed on the both sides of the conversion board 55 to connect the corresponding connection portions 54 of the upper and lower contact elements. The arranging pitch of the connection portions 54 and the contact portions of the card 53 is different from the arranging pitch of the circuit conductors of the circuit board 51. Usually the former pitch is coarser than the latter pitch.
In operation, the lower connector 56B is soldered to the circuit board 51 while the upper connector 56A is soldered to the conversion board 55. Then, the conversion board 55 is inserted into the connector 52, and the connection portions 54 of the connector 52 are soldered to the conversion board 55. The connectors 56A and 56B are then connected to thereby connect the card 53 to the circuit board 51 even if the arrangement pitch of the card 53 is different from the arrangement pitch of the circuit board 51.
In FIGS. 2 and 3, a connector 62 is divided into two connectors 62A and 62B. A conversion board 65 is made flexible. The connection portions 64B of contact elements of the lower connector 62B are connected to a circuit board 61 directly.
As best shown in FIG. 2, the connection portions 64A of contact elements of the upper connector 62A are soldered to the conversion board 65 which is soldered to the upper connector 56A.
As best shown in FIG. 3, the lower connector 62B is mounted on the circuit board 61, and the connection portions 64B of contact elements are soldered to the circuit board 61. Then, the upper connector 56A and the lower connector 56B are connected.
Even if the arrangement pitch of contact portions of a card is different from the arrangement pitch of circuit conductors of a circuit board, it is possible to connect the card to the circuit board via the conversion connector.
However, the above electrical connector has many soldering points and suffers not only low productivity but also poor connection by soldering. Also, it needs a conversion board and increases the manufacturing cost. When poor soldering is found at the connection portion 64B of the lower connector, it is necessary to disconnect the conversion connector for repair. Especially, in the connection portion 54 in FIG. 1, the repairing operation is very difficult because the conversion board is not flexible.
Furthermore, the conversion board makes the connector larger.